Furnace for steam-boilers



- 2 Sheets--Sl1eet 1.

(No Model!) P. F. DUNDON. FURNACE FOR STEAM BOILERS.

Patented Sept. 27, 1881.

2 Sheets-Sheet 2.

(No Model.)

P. F. DUNDON.

FURNACE FOR STEAM BOILERS.

No. 247,546. Patented Sept. 27,1881.

N. PETERS. FluulwLlllm mpher. wnlnu lun. D. C.

To all whom it may concern:

UNITED STATES PATENT OFFICE.

PATRICK F. DUNDON, OF SAN FRANCISCO, CALIFORNIA.

FURNACE FOR STEAM.-BOILERS.

SPECIFICATION forming part of Letters Patent No. 247,546, datedSeptember 2'7, 1881,

Application filed February 1,}881. (N0 model.)

Be it known that I, PA'rRicK F. DUNDON, of the city and county of SanFrancisco, State of California,haveinvented an Improved Smoke- ConsumingFurnace for Steam-Boilers; and I hereby declare the following to be afull, clear, and exact description thereof.

My invention relates to an improvement in that class of furnaces orapparatus which is intended to produce a more perfect and completecombustion of the fuel, and which are known as smoke-burners.

It consists in the construction of a furnace having a bridge-wall at itsrear end, with the top so curved toward the furnace, in combination witha blast of air or steam directed upon the surface of the fuel at anangle, so as to strikeitnear thebridge-wall,wherebyacountercurrent willbe induced, which will return the smoke, soot, and unburned particles orgases toward the front of the furnace to be projected downward upon theincandescent fuel, where it is ignited and consumed before escaping overthe bridgewall.

Referring to the accompanying drawings for a more complete explanationof my invention,

. Figure 1 is a longitudinal section of the furnace of a steam-boiler.Fig. 2 is a transverse section. Fig. 3 is a view of another form ofboiler, in which the bridge-wall is straight on top. Figs. 4 and 5 aresectional views.

A is a boiler of any suitable construction to which it is desired toapply my invention. B is the furnace-front. C is the furnace having thegrate-bars D, upon which the fuel is re ceived.

Behind the grate-bars is the bridge-wall E, which is built up to followthe outline of the bottom of the boiler or the crown of the furnace, andat only a short distance from it. The face of this wall is curved towardthe furnace at the top, so as to form a projection or overhang, F, whichmay preferably be in the form of acurve or partial arch, and it tends tothrow the flame and products of combustion toward the front of thefurnace before they are allowed to escape over the bridge-wall.

At the front upper portion of the furnace is a pipe, G, which extendsacross, as shown, and has small perforations made in its lower rearportion, so that steam introduced into the pipe F, thus creating acurrent over the top of the fuel and toward the front of the furnace.This current catches the smoke, soot, and unconsumed gases which arisefrom the partially-ignited fuel and prevent them from escaping at onceover the bridge-wall, but return them toward the front of the furnace,where they are caught by the steam-jets and thrown down upon theincandescent fuel, so that the com bustion is rendered more complete. 6

I form holes H through the bridge-wall in a line corresponding with theupper surface of the wall. These holes are at such a point above thesurface of the fuel as to allow the flame from it to pass through, andthis produces a heat which will ignite the smoke and unconsumed gaswhich may have passed over the wall, so that they will be consumedbefore they enter the flues or tubes of the boiler. These holes may behorizontal or inclined, and are either formed in the wall, or ofsections of pipe which may be built in, with suitable intervals betweenthem.

Steam is furnished to the pipe G from the steam drum or dome or from anydesired point, and the steam may be superheated or not, as is found mostdesirable.

It generally appears, and especially where coal is used as a fuel, thatthere will be a bed of incandescent fuel at the extreme rear of thefurnace, and next to the bridge-wall, and any additions of fuel made byfiring are usually near the front, so that the smoke and unconsumedgases produced by the imperfect combustion of this freshly-supplied fuelwill arise near the front, and the action of the air or steam blast, asbefore described, serves to retain them within the furnace, and to bringthem into intimate contact with the hottest part of the fuel by theaction of the blast. It 5 also causes aflame from the fire to passthrough the holes in the wall, and in aslightly-upward direction, onaccount of the position of the openings, so that it will meet andconsume any smoke, soot, or inflammable gases which may have escapedover the bridge-wall.

It will be seen that to produce the best re" sults the bridge-wallshould be carried up near to the bottom of the boiler or to the crown-vsheet, according to the form of boiler used, so as to equalize the draftat all parts of it. The form of the holes through it is not material;but I have found that when in an inclined position they will be the mosteffective.

I am aware that the bridge walls of fnrn aces have heretofore been madewith their upper edges pitched forward; and I vain also aware that theupper edges of the bridge-walls have been perforated to allow flame topass through and meet the escaping uncon sumed gases and hence I do notbroadly claim either of these ideas; but I am not aware that abridge-wall has heretofore been made where the upper edge conformed tothe formation of the boilershell and also pitched forward 5 nor am Iaware that such a formation of bridge'wall has been combined with a jetof steam or air escaping at a high velocity. Consequently,

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The bridge-wall of a boiler-furnace haw ing its upper surfaceapproximating in form and approaching to the bottom of the boiler, andwith the curved projecting flange or overhang, as shown, in combinationwith the steam or air blast jet-tube, which directs a blast so as tostrike the fuel upon the grate at an angle near the wall, whereby areturn-currcnt is inprovided with the oblique holes or perforations,

substantially as herein described.

, In witness whereof I have hereunto set my hand.

PATRICK F. DUNDON.

Witnesses:

S. H. Nounsn, FRANK A. BROOKS.

